2008-04-22_PERMIT FILE - C1981017 ‎(15)‎

• Permit No: C1981017
• IBM Index Class Name: PERMIT FILE
• Doc Date: 4/22/2008
• Section_Exhibit Name: Chapter II-B Operation Plan - Permit Area
• Media Type: D
• Archive: No

Chapter II
• - Obstructions to emergency and/or principal spillways;
- Properly cleaned, maintained dewatering devices;
- Sediment storage volume;
- Sloughing, tension cracks, piping, etc.
The sediment ponds have been designed to be dewatered after each
major runoff event. The ponds will be dewatered by natural seepage
and infiltration, or through the use of an automatic or manual
dewatering device. The automatic dewatering device is designed to
be non-clogging and to have a discharge rate that will achieve and
maintain the required detention time. The devices have been
located at the lower elevation of the 10-year storm capacity
volume, although not below the maximum elevation of the sediment
storage volume.
Sediment pond maintenance includes removal of sediment when
sediment storage exceeds 60% of the designed sediment volume.
• The ponds at Outfalls 001, 020 and 016 are cleaned as necessary,
throughout the year. Cleaning of the other sediment ponds is done
when ground conditions are dry enough to allow access by the
necessary equipment. This is generally in the summer, and cleaning
usually progresses from ponds at the lower elevations to ponds at
the upper elevations (according to the pattern of snowmelt).
The muck removed in cleaning of the sediment ponds is placed on the
Sutey coal refuse pile (MR. July 11, 1985). In addition, approval
has been given for placement of sediment pond cleanings on the rock
tunnel disposal area. (MR-8. March 15, 1988). Placement of pond
cleanings on the rock tunnel disposal area is done so as to
maintain surface slopes and adequate drainage of the pile. (MR-18.
July 1, 1989). Approval has been given for placement of pond
cleanings from the four ponds at Portals No. 1 and No. 2 on Pad #4,
which is a former storage area situated near the ponds (MR-28.
July 28, 1990). Approval has been given for continued placement of
• pond cleanings on the old refuse pile prior to topsoil placement
(MR-29. August 16, 1990).
In addition, ditches and culverts are inspected periodically and
cleaned as necessary to keep them open and free of debris. The
timing for clean-up at the end of winter also depends upon when the
ground dries enough to allow access for the necessary equipment.
5. Topsoil.
a. Existing Topsoil Stockpiles.
In the previous permit term (1983-1988) surface disturbance
resulted from expansion of the coal refuse disposal areas, the
Adit/Rock Tunnel spoil disposal area, and upgrading of the
hydrologic diversion and sediment control systems. Topsoil and
soil horizons, as required by MLRD, were salvaged and stored.
. 33
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